RELATE Vulnerable to Remote Code Execution (RCE) via Insecure Celery Pickle Deserialization

RELATE is a web-based courseware package. Prior to commit d66ba5659b459bf1ba56b7109b5f9ecf197cbefb, RELATE LMS configures its Celery workers to accept and deserialize untrusted 'pickle' data. An attacker who can reach the message broker can execute arbitrary commands on the host server. Combined with missing network isolation in the code execution sandbox, this allows an authenticated student to achieve full Remote Code Execution (RCE) on the host system. Commit d66ba5659b459bf1ba56b7109b5f9ecf197cbefb fixes the issue.